The disclosures of Japanese Patent Application Nos. HEI 11-8380 filed on Jan. 14, 1999, HEI 11-41255 filed on Feb. 19, 1999, HEI 11-116551 filed on Apr. 23, 1999, HEI 11-142247 filed on May 21, 1999, HEI 11-250770 filed on Sep. 3, 1999, HEI 11-266901 filed on Sep. 21, 1999 and 2000-003293 filed on Jan. 12, 1999 including the specifications, drawings and abstracts are incorporated herein by reference in their entirety.
1. Field of the Invention
The present invention relates to a sitting passenger detecting apparatus and a sitting passenger detecting method, and more particularly to a sitting passenger detecting apparatus which is applied to a seat disposed to be movable in the longitudinal direction on a floor of a vehicle, such as an automobile, and a sitting passenger detecting method.
2. Description of the Related Art
An example of a sitting passenger detecting apparatus disposed to be movable in the longitudinal direction on a floor of a vehicle, such as an automobile, has been disclosed in Japanese Patent application Laid-Open No. HEI 9-207638.
As shown in FIG. 51, the sitting passenger detecting apparatus incorporates load sensors 606 each of which is interposed between a seat joining portion 604 for joining a seat 600 to a floor 602 and a joining portion 602A of the floor 602. The number of the load sensors 606 is two which is the minimum number. The load sensors 606 are disposed at the two ends of a diagonal of the seat joining portions 604 which are usually provided for four portions. As a result, presence of a passenger on the seat 600 can reliably be detected regardless of the position of the passenger sitting on the seat 600. Moreover, an excessively large number of the load sensors is not provided so as to avoid a complex structure and the cost increase.
The foregoing sitting passenger detecting apparatus incorporates the load sensor 606 provided for a portion for joining the seat joining portion 604 provided for a lower rail of a seat track 610 and the floor 602 to each other. Therefore, when the seat 600 has been moved rearwards along the seat track 610 and a seat back 600A has been reclined rearwards, the load of the passenger resting against the seat back 600A sometimes causes an upward load to be applied to the front seat joining portion 604. As a result, the load sensor 606 provided for the front seat joining portion 604 cannot substantially measure the load. Hence it follows that the measuring accuracy cannot be improved.
When bolts 608 serving as clamping members are tightened strongly in order to increase the rigidity for supporting the seat 600, an initial value (initial distortion) of the load sensor 606 of the above-mentioned sitting passenger detecting apparatus is enlarged excessively. As a result, the variation (varied distortion) of the load sensor 606 which is caused by the load which must be measured is reduced with respect to the initial value. Since the variation with respect to the initial value is reduced as described above, the measuring accuracy cannot be improved.
An object of the present invention is to provide a sitting passenger detecting apparatus and a sitting passenger detecting method each of which is capable of improving an accuracy of measuring a load which is added to a seat.
According to a first aspect of the present invention, there is provided a sitting passenger detecting apparatus comprising: connecting members structured to separate a seat rail and a seat cushion frame from each other and use a load which is added to the seat cushion frame to connect the seat rail and the seat cushion frame to each other such that relative displacement between the seat rail and the seat cushion frame is permitted; displacement detecting means for detecting displacement between the seat rail and the seat cushion frame; and weight calculating means for calculating the weight of a passenger sitting on the seat in accordance with a value detected by the displacement detecting means.
Therefore, when a passenger sits on the seat, the seat cushion frame is relatively moved with respect to the seat rail. The relative displacement is detected by the displacement detecting means. In accordance with a detected value, the weight calculating means calculates the weight of the sitting passenger. Therefore, if the seat is slid in the longitudinal direction, the relative position between the seat rail and the seat cushion frame is not changed. As a result, the load which is added to the seat can accurately be measured. Hence it follows that the accuracy of measuring the weight of the passenger sitting on the seat can be improved.
The sitting passenger detecting apparatus according to the first aspect incorporates the connecting member which is a bracket provided for at least the rear connecting portion of the front and rear connecting portions between the upper rail of the seat rails and the seat cushion frame. When a load is added to the seat cushion frame, the bracket is compressed and deformed downwards. The displacement detecting means is a sensor for detecting change in the distance from the seat rail to the seat cushion frame. The sensor may be disposed in parallel with the bracket at an offset position in a direction of the width of the seat.
When a passenger has sat on the seat, the load added to the seat cushion frame downwards compresses and deforms the bracket. Thus, the distance between the seat cushion frame and the bracket is shortened. Since the foregoing change is detected by the sensor, the accuracy of measuring the weight of the passenger sitting in the seat can be improved. If the upper rail and the seat cushion frame are firmly joined to each other, the foregoing state does not exert a great influence on the displacement of the sensor joining portion. As a result, the seat support rigidity can be increased without any deterioration in the measuring accuracy of the sensor. As a result, the comfort of the seat can be improved.
The foregoing sensor may comprise a thin plate which is distorted in accordance with change in the distance from the seat cushion frame and the upper rail; and a sensor body for detecting distortion of the thin plate.
As a result of employment of the foregoing structure, the thin plate is distorted when the distance between the seat cushion frame and the upper rail has been changed. The distortion is detected by the sensor body. Thus, the structure can be simplified.
The foregoing bracket is characterized by a bending portion which is elastically deformed in a downward direction owing to the load which is added to the seat when a passenger has sat in the seat.
As a result of employment of the foregoing structure, the load which is added to the seat after the passenger has sat in the seat elastically deforms the bending portion of the bracket. As a result, the distance between the seat cushion frame and the upper rail can be-changed, causing the structure to be simplified.
The connecting member may be a link for connecting the seat rail and the seat cushion frame to each other. The displacement detecting means may be a sensor for detecting the relative displacement between the link and the seat cushion frame occurring when the passenger has sat on the seat.
As a result, when the passenger has sat on the seat, relative displacement occurs between the link and the seat cushion frame. The sensor detects the relative displacement so that the weight of the passenger sitting on the seat is accurately measured.
A structure may be employed which incorporates the bracket which connects two pin-support points on the seat cushion frame to each other and to which the upper end of the link is connected. The sensor joined to the bracket measures the distortion of the bracket.
As a result, when the passenger has sat on the seat, the seat cushion frame is downwards pushed. Thus, the bracket is downwards deformed such that the connecting pin disposed at the upper end of the link serves as a steady point. Then, distortion of the bracket occurring when the foregoing downward deformation has taken place is detected by the sensor. The weight of the passenger who has sat on the seat can accurately be detected. Moreover, the bracket may be structured to have a certain width in the direction of the width of the vehicle. Since the bracket has the certain width in the direction of the width of the vehicle, the rigidity in the direction of the width of the seat required for the seat can be maintained.
The seat cushion frame may have a hole into which a pin for connecting the bracket and the upper end of the link to each other has been inserted such that a predetermined gap is retained in the vertical direction.
As a result, the hole formed in the seat cushion frame permits the seat cushion frame and the bracket to freely be moved in the vertical direction with respect to the link. If rotational force is added to the sheet owing to collision or the like and, therefore, the sheet is greatly moved in the vertical direction, the pin and the portion around the hole are made contact with each other. Thus, furthermore deformation of the bracket can be prevented. As a result, breakage of the bracket can be prevented.
The connecting member may be two cross bars which are disposed between the right and left seat cushion frames and to which a cushion pan has been joined. The foregoing displacement detecting means may be a sensor provided for the cross bar to measure distortion of the cross bar.
As a result, when the passenger has sat on the seat, the load which acts on the seat cushion pan downwards deforms the cross bar. The caused distortion of the cross bar is measured by the sensor. In accordance with a detected value, the weight of the passenger sitting in the seat can be calculated. Any great influence of the attitude of the passenger sitting in the seat and a joint error of the seat rail is not exerted on the result of the calculation. Therefore, the accuracy of measuring the weight of the passenger sitting on the seat can be improved with a simple structure.
A structure may be employed which incorporates a back bar arranged between right and left seat back frames and a seat back sensor joined to the back bar to measure change in the distance from the seat back cushion spring, and wherein the weight calculating means calculates the weight of the passenger sitting on the seat in accordance with a value detected by the sensor provided for the cross bar and a value detected by the seat back sensor.
As a result, the reclining angle of the seat back is not used when the weight of the passenger sitting on the seat can accurately be measured in accordance with the value detected by each of the sensors provided for the two front and rear cross bars and the value detected by the sensor provided for the seat back.
A structure may be employed which incorporates the right and left seat cushion frames and the seat rail which are offset in the direction of the width of the vehicle, wherein the connecting member is two front and rear sensor bars extending in the direction of the width of the vehicle and structured to connect the right and left seat cushion frames and the seat rail to one another, and the displacement detecting means is sensors disposed between the seat cushion frame connecting portion and the seat rail connecting portion at the two ends of the two sensor bars to detect distortion of the sensor bar.
As a result, after the passenger has sat on the seat, a load is added to the seat cushion frame. Thus, distortion occurs between the seat cushion frame connecting portion and the seat rail connecting portion. The distortion is detected by the sensor to measure the weight of the passenger. Since the two front and rear sensor bars connect the right and left seat cushion frames and the seat rail to one another, the right and left seat rails are made to be in parallel with each other when the seat rails are mounted on the body of the vehicle. As a result, an error made when mounting on the body does not cause needless distortion of the sensor bar to occur. Moreover, any great influence of the attitude of the sitting passenger is not exerted on the distortion of the sensor bar. Therefore, only a simple structure is required to accurately measure the weight of the sitting passenger.
A thickness-reduced portion may be formed in each of the portions of the two sensor bars in which the sensors are disposed.
As a result, the thickness-reduced portions provided with the sensors are reliably distorted after the passenger has sat on the seat. Therefore, the weight of the sitting passenger can furthermore accurately be measured.
A structure may be employed in which the front and rear connecting portions between the upper rail of the seat rail and the seat cushion frame are joined by rotative links, an elastic member is provided for at least either of the connecting portions so as to stably hold the seat cushion frame and an amount of displacement of the seat cushion frame with respect to the upper rail against urging force of the elastic member is detected by a variable resistor.
An amplifying means may be provided which amplifies the angle of rotation of the link to communicate a result of the amplification to the variable resistor.
As a result, after the passenger has sat on the seat, the load added to the seat cushion frame causes the seat cushion frame to relatively be displaced with respect to the upper rail against the urging force of the elastic member. The amount of the displacement is detected by the variable resistor. At this time, the amplifying means amplifies the angle of rotation of the link to communicate a result of the amplification to the variable resistor. As a result, the width of the change in the output of the signal from the variable resistor can furthermore be enlarged.
In the first aspect of the present invention, there is provided a deformation detection sensor disposed on a lower rail portion of the seat rail for detecting a predetermined deformation thereon and alarm means for alarming based on output signals of the deformation sensor.
The weight of the passenger sitting on the seat may not be measured accurately when the lower rail portion of the seat rail is deformed owing to the vehicle collision or the like. In the aforementioned construction, however, the deformation occurred in the lower rail portion can be detected by the deformation detection sensor and the passenger is alarmed to abnormality in the sitting passenger detecting function by the alarm means.
There also can be provided with another alarm means for alarming in the case where a changing rate of output signals from the sensor disposed in parallel with the bracket disposed either at the inner side or the outer side in a lateral direction of a vehicle exceeds a predetermined change rate.
When the seat rail and the seat cushion deform owing to the vehicle collision, the weight of the sitting passenger may not be measured accurately. In the above case, the passenger is alarmed to abnormality in the sitting passenger detecting function by the alarm means when a changing rate of output signals from the sensor disposed in parallel with the bracket disposed either at the inner side or the outer side in a lateral direction of a vehicle exceeds a predetermined change rate.
The sensor bar is divided into left and right portions such that each sensor bar has a different spring constant.
The above construction may prevent the left and right sensor bars from resonating even when they vibrate on the vacant seat during running of the vehicle because of the different spring constants of the left and right sensor bars. As a result, lateral vibration of the seat back caused by inversion of vertical resonance phase of the respective sensor bars can be suppressed.
According to a second aspect of the present invention, there is provided a sitting passenger detecting apparatus comprising: first load detecting means for detecting a load added to the front portion of a seating surface of a seat of a vehicle; second load detecting means for detecting a load added to the rear portion of the seating surface; first determining means for determining a fact that a passenger which is sitting on the seat is an adult when the sum of values detected by the first and second load detecting means is not smaller than a first threshold value; and a second determining means for determining a fact that a passenger which is sitting on the seat is an adult when a value detected by the first load detecting means is not smaller than a second threshold value and a value detected by the second load detecting means is not smaller than a third threshold value.
According to a third aspect of the present invention, there is provided a sitting passenger detecting method comprising the steps of: a first load detecting step for detecting a load added to the front portion of a seating surface of a seat of a vehicle; a second load detecting step for detecting a load added to a rear portion of the seating surface; a first determining step for determining a fact that a passenger sitting on the seat is an adult when the sum of values detected in the first and second load detecting steps is not smaller than a first threshold value; and a second determining step for determining a fact that a passenger which is sitting on the seat is an adult when a value detected in the first load detecting step is not smaller than a second threshold value and a value detected in the second load detecting step is not smaller than a third threshold value.
According to the second and third aspects, the sum of the loads added to the front and rear portions of the seating surface of the seat corresponds to the overall load (hereinafter called a xe2x80x9cseat loadxe2x80x9d) added to the seating surface of the seat. Therefore, when the sum of the values detected by the first and second load detecting means or in the first and second load detecting steps is not smaller than the first threshold value, a determination can be made that the passenger sitting on the seat is an adult. Note that the first threshold value is determined in accordance with an upper limit of the weights of children.
When an adult passenger has sat on the seat such that the seat back is inclined, the weight exerted from the body of the passenger to the seat back is enlarged. Therefore, the seat load is reduced. Also in the foregoing case, a load corresponding to at least the weight of the body of the passenger is added to the front portion of the seating surface of the seat. Therefore, when the value detected by the first load detecting means or in the load detecting step is not smaller than the second threshold value and the value detected by the second load detecting means or in the load detecting step is not smaller than the third threshold value, a determination can be made that the passenger sitting on the seat is an adult. The second threshold value is determined in accordance with the weight of the body of an adult passenger. The third threshold value is determined in accordance with a value obtained by subtracting the third threshold value from the upper limit of the weights of children.
As described above, according to the second and third aspects, if a passenger sits on the seat such that the seat back is inclined, only detection of the loads added to the front and rear portions of the seating surface of the seat enables a determination of the physique of a passenger, that is, whether the passenger is an adult or a child, to accurately be determined.
In the foregoing case, a third determining means may furthermore be provided which determines that the passenger sitting on the seat is an adult when at least either of values detected by the first and second load detecting means is not smaller than a fourth threshold value. A third determining step may furthermore be provided in which a determination is made that the passenger sitting on the seat is an adult when at least either of values detected in the first and second load detecting steps is not smaller than a fourth threshold value.
When an adult passenger has sat on the seat at a relatively front position, the weight of the passenger exerted from the feet of the passenger on the floor is enlarged. Thus, the seat load is reduced. In the foregoing case, the seat load is sometimes smaller than the first threshold value. However, at least either of the loads added to the front and rear portions of the seating surface of the seat is a value not smaller than a predetermined value which is larger than the weights of children. Therefore, when at least either of the values detected by the first and second load detecting means or at least either of the values detected in the first and second load detecting steps is not smaller than the fourth threshold value, a determination can be made that the sitting passenger is an adult. The fourth threshold value is determined in accordance with the upper limit of the weights of children.
When a passenger has worn a seat belt, the waist of the passenger is restrained by the seat belt. Thus, a consideration can be made that the passenger deeply sits on the seat of the vehicle. In the foregoing case, the weight of the passenger is added to a relatively rear portion of the seating surface of the seat. When a child passenger restraining apparatus (for example, a child seat) facing rearwards is secured by the seat belt, the center of gravity of the child restraining apparatus including the child passenger is moved to the front portion of the seat. Thus, the load of the child restraining apparatus is added to the relatively front portion of the seating surface of the seat. Therefore, a seat-belt joining determining means or a seat-belt joining determining step may be provided so that a result of the determination and values detected by the first and second load detecting means or in the first and second load detecting steps are used to determine whether the child restraining apparatus is joined to be directed rearwards.
In the foregoing case, a structure may be employed in which when the seat belt has been joined and a value detected by the first load detecting means or in the load detecting step is not smaller than a value detected by the second load detecting means or in the second load detecting step, a determination is made that the child restraining apparatus is joined to be directed rearwards.
According a fourth aspect of the present invention, there is provided a sitting passenger detecting apparatus comprising: a seat track disposed between a floor and a seat cushion frame to permit movement of the seat cushion frame in the longitudinal direction with respect to the floor; and a load sensor for detecting a load added to the seat cushion frame in accordance with displacement of the seat cushion frame with respect to an upper rail of the seat track.
Therefore, when the seat has been moved in the longitudinal direction, the movement of the upper rail of the seat track inhibits change in the relative position of the seat cushion frame with respect to the upper rail. As a result, the longitudinal position of the seat does not exert an influence on the displacement of the seat cushion frame with respect to the upper rail caused from the sitting passenger. Hence it follows that the load sensor is able to accurately measure the load added to the seat cushion frame in accordance with the displacement of the seat cushion frame with respect to the upper rail.
According to a fifth aspect of the present invention, there is provided a sitting passenger detecting apparatus comprising: a seat track disposed between a floor and a seat cushion frame to permit movement of the seat cushion frame in the longitudinal direction with respect to the floor; a front connecting portion for connecting the front portion of the seat cushion frame and the front portion of the upper rail of the seat track to each other; and rear connecting portion for connecting the rear portion of the seat cushion frame and the rear portion of the upper rail to each other; a load sensor disposed in a joining portion formed at an offset position in the direction of the width of the seat with respect to the rear connecting portion and arranged to detect a load added to the seat cushion frame in accordance with displacement of the seat cushion frame with respect to the upper rail; and a low-strength portion formed between the rear connecting portion of the upper rail and the sensor joining portion.
Therefore, when the seat has been moved in the longitudinal direction, the movement of the upper rail of the seat track inhibits change in the relative position of the seat cushion frame with respect to the upper rail. As a result, an influence of the longitudinal position of the seat is not exerted on the displacement of the seat cushion frame with respect to the upper rail caused from the sitting passenger. Therefore, the load sensor is able to accurately measure the load added to the seat cushion frame in accordance with the displacement of the seat cushion frame with respect to the upper rail.
The sensor joining portion is provided at the position offset in the widthwise direction of the seat with respect to the rear connecting portion. Moreover, the low-strength portion is formed between the rear connecting portion of the upper rail and the sensor joining portion. Therefore, if the upper rail and the seat cushion frame are firmly joined to each other, any influence is exerted on the displacement of the seat cushion frame with respect to the upper rail. As a result, the rigidity for supporting the seat can be increased without any deterioration in the measuring accuracy of the load sensor so that the seat sitting comfort of the passenger is improved.
In the front connecting portion, the seat cushion frame may rotatively be connected to the upper rail.
As a result, the load of the passenger sitting on the seat causes the seat cushion frame to downwards be rotated with respect to the upper rail such that the front connecting portion serves as the center of the rotation. As a result, the displacement of the seat cushion frame with respect to the upper rail can effectively be transmitted to the load sensor. Thus, the load added to the seat cushion frame can furthermore accurately be measured.
A sound insulating member may be disposed between the sensor joining portion of the upper rail and the sensor joining portion of the seat cushion frame.
If the vehicle runs on a rough area or the like, noise generated when the sensor joining portion of the upper rail and sensor joining portion of the seat cushion frame are brought into contact with each other after a gap has been formed between the two portions owing to movement of the passenger can be prevented by the sound insulating member.
According to a sixth aspect of the present invention, there is provided a sitting passenger detecting apparatus comprising: at least one load detecting means for detecting a vertical load added to a seat body joined to a car-body member; seat-belt load detecting means for detecting a load caused from a tension of the seat belt added to a seat belt anchor secured to the car-body member; direction detecting means for detecting the direction of the load caused from the tension; and estimating means for estimating the weight of the passenger in accordance with the load detected by the load detecting means, wherein the estimating means estimates the vertical load added in between the car body and the seat body owing to the load caused from the tension and subtracts the estimated load from the load detected by the load detecting means so as to estimate the weight of the passenger.
Therefore, the load caused from the tension of the seat belt added to the seat belt anchor is detected, the direction of the load caused from the tension of the seat belt is detected, the vertical load added in between the car-body member and the seat body owing to the load caused from the tension of the seat belt is estimated, and the weight of the passenger is estimated by subtracting the estimated load from the load detected by the load detecting means. Therefore, exertion of the load caused from the tension of the seat belt is inhibited when the weight of the passenger is accurately obtained.
The seat body may be secured to the car-body member through a joining member and the load detecting means may be disposed adjacent to the seat body as compared with the position between the car-body member and the joining member when the positional relationship is viewed along the passage through which the load is transmitted from the seat body to the car-body member.
According to a seventh aspect of the present invention, there is provided a sitting passenger detecting apparatus comprising: at least one load detecting means disposed between a car-body member and a seat body disposed above the car-body member and arranged to detect a vertical load added in between the car-body member and the seat body; and estimating means for estimating the weight of a passenger in accordance with the load detected by the load detecting means, wherein a seat belt anchor is disposed adjacent to the seat body as compared with the load detecting means when the positional relationship is viewed along the passage through which the load is transmitted from the seat body to the car-body member.
As described above, the seat belt anchor is disposed adjacent to the seat body as compared with the load detecting means when the positional relationship is viewed along the passage through which the load is transmitted from the seat body to the car-body member. Thus, the load caused from the tension of the seat belt is not added to the load detecting means. Therefore, the weight of the passenger can accurately be detected by the load detecting means without any influence of the load caused from the tension of the seat belt.
The seat body may be secured to the car-body member through the joining member and the load detecting means may be disposed adjacent to the seat body as compared with the position between the car-body member and the joining member when the positional relationship is viewed along the passage through which the load is transmitted from the seat body to the car-body member.
As described above, the load detecting means is disposed adjacent to the seat body as compared with the car-body member and the joining member when the positional relationship is viewed along the passage through which the load is transmitted from the seat body to the car-body member. Also an influence of change in the load for joining the seat body to the car-body member by using the joining member can reliably be eliminated.
According to an eighth embodiment of the present invention, there is provided a sitting passenger detecting apparatus comprising: at least one load detecting means disposed between a car-body member and a seat body disposed above the car-body member and arranged to detect a vertical load added in between the car-body member and the seat body; estimating means for estimating the weight of a passenger in accordance with the load detected by the load detecting means; and seat-belt-load maintaining means disposed between the car-body member and the seat body and arranged to maintain a load added from the seat belt to the seat body.
Therefore, the load added from the seat belt to the seat body is maintained by the seat-belt-load maintaining means disposed between the car-body member and the seat body. Thus, the load caused from the tension of the seat belt is not substantially added to the load detecting means. Therefore, the weight of the passenger can accurately be detected by the load detecting means without any influence of the load caused from the seat belt.
The seventh and eighth aspects may be structured such that the seat belt anchor is secured to the seat member integrated with the seat body and the load detecting means is disposed between the seat member and the car-body member.
The sixth to eighth aspects may be structured such that a relative-displacement permitting means for permitting the seat body to relatively be displaced in at least the vertical direction with respect to the car-body member owing to the weight of the passenger is disposed between the car-body member and the seat body. Moreover, the load detecting means may be structured to detect change in a physical quantity occurring when the seat body is relatively displaced with respect to the car-body member.
The eighth aspect may be structured such that the relative-displacement permitting means incorporates a plurality of link members pivotally supported by the car-body member and the seat body and relatively inclined in the vertical direction at positions apart from one another.
Each link member may be structured to extend to incline rearwards of the vehicle with respect to the vertical direction when the positional relationship is viewed in a direction from a lower end of the link member to the upper end of the same.
At least one link member is structured to serves as a seat-belt-load maintaining means.
At least one link member may be disposed at substantially the same position of a seat belt in a state of use by a passenger of a standard physique when the positional relationship is viewed in the lateral direction of the vehicle.